Telephone system



Filed May 5, 1930 2 Sheets-Sheet 1 l\ my,

INVENTOR WILLIAM J. VlNCENT ATTORNY Sept. 1, 1931. w. J. VINCENT1,321,193

TELEPHONE SYSTEM Filed May 5, 1930 2 Sheets-Sheet 2 OPERATE SLOW TO TOIN TERRUPTER INVENTOR WILLIAM J. VINCENT BYA ATTORNEY Patented Sept. 1,1931 UNITED STATES PATENT orrice WILLIAM J. VINCENT, OF ROCHES ER, NEWYORK, AssIGNoIt'ro THE ROCHESTER TELEPHONE CORPORATION, OF nocr'rnsr'nn,NEW YonK, A oonronerron or rvnw YORK TELEPHONE SYSTEM Application filedMay 5, 1930. Serial No. 450,047.

This invention relates to telephone systems and more particularly tomanual telephone systems.

In the past it has been the practice in manual telephone systems,especially in the case where the busy called line terminated in the sameexchange as the calling telephone line, to provide at least one busybackjack into which the operator plugged the calling end of a cord circuitconnected to a calling telephone line which desired connection to acalled line that tested busy. As long as this cord circuit was connectedto such a busyback jack, a source of the busy tone current was extendedto the calling telephone line which caused a distinctive signal in thereceiver of the calling telephone line to indicate to the subscriberthere-at that the wanted line was busy; In such a system it wasnecessary for the operator to insert the calling plug of such a cordcircuit into a busyback jack and subsequently to .remove the plug fromthat jack when it was desired to terminate the busyback signal.- Theseoperations required a considerable amount of time which otherwise couldbe used'in establishing useful connections.

In accordance with the present invention the need for busyback jacks hasbeen obviated by providing a busyback key and associated equipmentcommon to all of the cord circuits 0]": an operators position so that assoon as a called line tests busy it is merely necessary for the operatorto depress this key after which the busyback signal is transmitted tothe callin telephone line until the subscriber aba-ndbns the call orinitiates a recall. A further feature of the invention includes the useof the ringing relay of a cord circuit to control the application of thebusyback tone tothe calling tele-' phone line. These and other featureswill appear from the detailed description and an pended claims.

For a clearer understanding of the invention reference is made to thedrawings in represented one of a plurality of telephone lines which maybe a calling line while thei'ji center portion of this figure andaportion of Fig. 2 abovethe brokenline represent equipment individual toa cord circuitlof which there may be several located at each operatorsposition. In the upper right-L55 hand corner of Fig. lthere'isrepresented a called telephone line while the portion of Fi 2below the broken line represents the equipment common to the cordcircuits of an operators position. i v 11.60 It is believed that thepresent system will best be understood by describing the operationsinvolved in establishing a telephone connection from a calling to acalled telephone line. 7 255 When the calling subscriber at substation Ainitiates a call by removing his receiver from its switchhook, the linerelay 5 is energized through the back contacts of the cutoff relay 6over the two sides of the calling linezfim in series. The operation ofthe line-relay lights the lamp 7 indicating that a call is awaitingattention whereupon the operator inserts the plug P of an idlecordcircuit into-the jack J of the calling line. The answering supervisoryrelay 8 is then operated to prevent the lighting of the answeringsupervisory lamp 9, in a circuittraceable from grounded battery throughtwo. of the windings of the repeating coil,' winding of relay? to 8, thetip and ring conductors of the cord circuit and thence through the plugP and jack J-over the'two sides of the calling line in series. I i

Adso when the plug P is inserted injack cfi J the cutofl relay 6 isoperated to disconnect the linerelay from the control of the callingline whereupon the line lamp 7 is extinguished. The energized circuit ofthe cutoff relay 6 extends from ground, windingap of this relay, sleevecontacts of the jack J and plug P. sleeve conductor 10, winding of thesleeve relay 11 to grounded battery. The relay 11 is likewise operatedover the circuit just described and eii'ects the energi- Zation of theautomatic listening relay 12 which connects the operators telephone set(not shown) over the conductors 13 to the answering endof'the cordcircuit taken for use. The energizing circuit forthe listen Lil ingrelay 12 is completed from grounded battery, inner armature and frontcontact of sleeve relay 11, conductor 14, winding of the relay 12,conductor 15, uppermost continuity spring and contact of relay 16,conductor 17, to ground at the lower armature and contact of relay 18.The operator now inquires for the number of the wanted line which isassumed to be the line terminating at the substation B and then testsfor the busy or idle condition of this line by touching the tip of theplug P to the jack J Since the sleeve of this line is connected tobattery when the line is busy, this busy condition is indicated by adistinctive click in the operators headset when the tip of the plug Ptouches the sleeve of the jack J. If, however, the line is idle at thetime of making such a test, the operator hears no click indicating thatthe call may be completed she inserts the plug P into the jack J.

As soon as the plug P engages the jack J the sleeve relay 19 isenergized from grounded battery, winding of this relay, sleeve contactsof plug P and jack J, winding of the called line cutoff relay 20 toground. The operation of the relay 19 closes a circuit from groundedbattery, its uppermost armature and front contact, conductor 21, inner,back contact and armature of relay 18, conductor 22, winding of relay23, to ground, causing the operation of this last named relay. Theoperator now depresses the ringing key 24 which results in the operationof the relay 25 from grounded battery, winding of this relay, ringingkey contacts 24-. to ground. lVith the relays 23 and 25 energized, anoperating circuit is C0111- pleted for the relay 26 from groundedbattery, winding of this relay, front contact and armature of relay 25,inner, lower front cnnimtand armature of relay 23 to ground.

The ringing relay 28 is now energized from ground at the lowermost backcontact and of relay 29, conductor 30, armature and back contact of triprelay 81, winding of relay28, conductor 32, front contact and armatureof relay 12, conductor 34-, lowermost armature and front contact ofrelay 23, front contact and armature of relay 26, through the resistanceunit to grounded battery. Relay 28 when thus operated closes a lockingcircuit for itself from grounded battery, inner armature and frontcontact of relay 19, conductor 35, back contact and upper armature ofrelay 16, conductorc36, armature, front contact, and winding of relay 28and thence to ground at the armature and back contact of relay 29 overconductor 30. Relays 23 and 26 in turn effect the operation of the relay27 from grounded battery, winding of this relay, inner front contactsand armatures of relays 26 and 23 to ground. The relay 27 is sluggish inat tracting its armature in order to insure the energization of theringing relay 28 before the operation of the relay 18 which last namedrelay is effective to effect the release of relay 12 which in turndisconnects the operators telephone set from the cord circuit now inuse. The energizing circuit of relay 18 extends from grounded battery,inner armature and front contact of relay 19, conductor 35, winding ofthe relay 18, front contact and upper armature of relay 12, conductor37, inner, upper, back contact and armature of relay 38, front contactand armature of relay 27, to ground. Relay 18 when thus energized closesa locking circuit for itself from ground, through its own continuityspring and contact 39 and its own winding, and thence to groundedbattery, over conductor 35 as previously oescribed. The relay 18 at itslowermost armature and back contact opens the holding circuit of theautomatic listening relay 12 which deenergizes and disconnects theoperators telephone set from this cord circuit. At the innermost, upperarmature and back contact of relay 18, the energizing circuit of therelay 23 in the common key circuit is opened causing the relays 25, 26and 27 to decnergize thereby permitting the common key equipment torevert to use on other cord circuits.

As soon as the ringing relay 28 is energized, ringing current issupplied to the called line from the ringing current source,

upper winding of the trip relay 31, lower,

back contacts and armatures of relays and 71, innermost front'contactand lower armature of relay 18, lower front contact and armature ofrelay 28, ring contacts of plug P and jack J thence over the called lineand through the ringer atsubstation B, over the upperside of the calledline, tip contacts of the jack J and plug P, uppermost front contact andarmature of relay 28 to ground at the uppermost back contact andarmature of relay 71. Ringing current is supplied over this circuituntil the called party responds at which time the trip relay 31 isoperated and at its armature and back contact interrupts the lockingcircuit for the ringing relay 28 which deenergizes and closes the breakpoints which existed in the talking leads of the cord circuit so thatthe calling and called substations are now connected over aconversational circuit.

The present system is equipped with party line ringing whereby any oneof four substations on a telephone line may be selectively signalled. Inorder to select ringing current of the proper frequency to signal awanted station on a party line, four ringing keys 2%, 74, and 7 6' areprovided for the common use with all of the cord circuits of anoperators position. It has previously been described that when theringing key 24 is depressed proper ringing current to signal thesubstation B having designation W, is applied to the called line. In theevent that it is desired to signal another subscriber on this line whosedesignation may be R the ringing key 74 is depressed which results inthe operation of the relay 77. This effects the energization of theringing current selecting relay 70 in a circuit traceable from ground,upper armature and front contact of relay 77, conductor 78, lowerarmature and front contact of relay 12, winding of relay 70, conductor79, conductor 35, inner, front contact and armature of relay 19 togrounded battery. Relay 70 when thus energized locks itself operatedfrom ground at the back contact and armature of relay '29, conductor 30,armature and back contact of relay 31, conductor 80, front contact,armature and winding of relay 7O thence to grounded battery overconductor 79 as previously described. In the event that the operatordesires to. signal a called subscriber whose designation may be J,ringing key 75 is depressed to operate relay 81. This results in theenergization and subsequent locking of relay 71 over circuits similar tothose just described for the relay 70. If, however, it is desired tosignal the called party whose designation may be M, ringing key 76 isdepressed to operate the relay 82. This in turn results in theenergization and subsequent locking of both ringing selective relays 7 0and 71. The operated or non-operated condition of relays 70 and 71determines the character of ringing current which is applied through thetrip relay 31 to the called line.

If the wanted subscribers line terminates in another exchange, theoperator inserts the plug P into the jack J2 ofa' trunk leading to thatexchange where the call may be completed by a second operator. Theoriginating operator then depresses the trunk key 40 which is effectiveto operate the relay 41. On the operation of this relay a circuit isclosed from ground, its lower armature and front contact, conductor 37,armature and front contact of relay 1'2, winding of relay 18, conductor35, inner front con'fact and armature of sleeve relay 19,'to ground. Asindicated in the case of a local call, the relay 18 effects thedeenergization of the relay 12 which in turn disconnects the operatorstelephone se'; from the cord circuit just taken for use. In the case ofsuch a trunk call the ringing relay 28 is not operated and consequentlyno ringing current is transmitted over the selected trunk.

The present system is provided with an arrangement whereby completedcalls may be charged to a calling subscriber. As soon as the call hasproceeded to the pointwhere the relay 19 operates the slow releasingrelay 42 is energized in a circuit from grounded battery, uppermostarmature and front contact of relay 11, winding of relay 42,

.middle armature and front contact of relay 18, upper armature and backcontact of relay 44, conductor 30, lower armature and 3 back contact ofrelay 29, to ground. Vhen the call has proceeded to the point where thecalling supervisory relay 46 is energized on the response of the calledparty, a'circuit is extended from ground, armature and;

front contact of relay 46, conductor 48, winding of'relay 44, conductor35, inner, front contact and armatureof relay 19, to grounded battery.Relay 44 is energized in this circuit and effects theoperationor.

relay 43 in a circuit traceable from grounded battery, winding of therelay, lowermost front contact and armature ofrelay 44,'ar mature andfront contact of relay 42 to ground. lVhen the relay 43 operates, it

completes at its lower armature and front contact an energizing circuitfor the slow operating relay 45. The metering circuit is now closed froma source of high potential current (not shown) over conductor 49'scribed so thatthe calling line meter is operated, once and once only,over the metering circuit 49, on the completion of each call.

If, how-ever, a call shouldnotbe charged to the calling substation, thenon-register key 83 is depressed; This results in the operation of therelay 44 into a circuit extending from ground, closed contacts of key83, conductor 84, lower armature and front contact of relay12,conductors 85 and 48,

winding of relay 44, conductor 35, front contact and armature of relay19 to grounded battery. Under the non-register condition, the relay 44operates to prevent the energization of relay 42 in Fig. 1 so that it simpossible to complete the metering circuit and consequently meteringcurrent is not applied to the sleeve circuit 10 of the calling line. i r

If the calling subscriber desires to regain" battery, uppermost armatureand cont-act of- When the relay 45 scribed.

relay 11, back contact and armature of relay 8, through the resistanceunit, back contact, continuity spring and winding of the relay 29,conductor 50, uppermost front con tact and armature of relay 18,normally closed contacts of the listening key 51 to ground. The relay 29as soon as it 18 operated closes a locking circuit for itself from.grounded battery, its uppermost armature, front contact and winding andthence to ground over conductor 50 as previously de- Also when relay 29is operated the lamp 9 associated with the calling line isintermittently lighted in the following manner. An energizing circuit isclosed for the lamp 9 from grounded battery, armature and front contactof relay 29, through the resistance unit, lamp 9, front contact andarmature of relay 11, to ground. Also at the inner armature and frontcontact of relay 29, a circuit is closed from grounded .relay 53, lowerwinding of relay 54 to ground. This last described circuit shunts thelamp 9 but energizes the relay 51 which closes a circuit over conductor55, from the interrupter (not shown), front contact and armature ofrelay 54, winding of relay 53 to grounded battery. The relay 53 isintermittently operated in accordance with the adjustment of theinterrupter and on each operation of this relay at its back contact andcontinuity spring it interrupts the conductor which has been shortcircuiting the lamp 9 permitting it to operate. During the time that therelay 53 is operated the relay 54 is held operated through both of itswindings in series but when relay 53 deenergizes relay 54 is heldoperated through its lower winding.

In the past it has been the practice on local calls when a linetested-busy to insert the answering plug such as P of the cord circuittaken for use into a busyback jack through which an interruptedbusy tonewas supplied over this cord circuit to the calling line. In the case ofsuch a busy call the operators time was unnecessarily taken up inplugging into the busyback jack and subsequently taking down thatconnection. In accordance with the present invention it is proposed toprovide a busyback key 57 which is common to all of the cord circuits atan operators position so that when a called line tests busy it is onlynecessary for the operator to depress the busyback key momentarily afterwhich the busy tone is transmitted to the calling line until the subscriber hangs up or until the answering plug is withdrawn from thecalling jack, or until the operator subsequently tests the busy line,

finds it idle and completes the connection thereto.

The depression of the busyback key 57 effects the energization of theslow releasing relay 38 from grounded battery, winding of this relay,contacts of the key 57, back contact and armature of relay 23 to ground.As soon as relay 38 operates, at its lower most front contact andarmature, it completes an energizing circuit for the slow operatingcircuit 27. The operation of the relays 27 and 38 complete a circuitfrom ground, armature and front contact of relay 27, middle armature andfront contact of relay 38, conductor 58, contact of relay 12, winding ofrelay 16, innermost front contact, and armature of sleeve relay 11 togrounded battery. Relay 16 when operated closes a locking circuit foritself from grounded battery, inner armature and front contact of relay11, winding of relay 16, its innermost lower front contact and armature,conductor 59, contacts of the manual listening key 51 to ground. At theback contact and continuity spring of relay 16 the energizing circuit ofthe automatic listening relay 12 is opened, permitting this relay todecnergize so that the operators telephone set may be used in connectionwith other cord circuits. Before relay 12 releases the ringing relay 28is operated from ground at the back contact and armature of relay 29,conductor 30, armature and back contact of trip relay 31, winding-of theringing relay 28, conductor 32, front contact and armature of relay 12,conductor 34, uppermost armature and front contact of relay 38 throughthe resist ance unit to grounded battery. On the operation of the relay28, it looks itself energized from grounded battery, inner armature andfront contact of relay 11, front contact and armature of relay 16,conductor 36, rmature, front contact and armature of relay 28, andthenceto ground over conductor 3O previously described.

It will be noted that although the ringing relay 28 is energized, theringing current is ineffective since the plug P is not inserted into thejack of the called line but instead busy tone current is supplied fromthe source BZ over conductor 60, lowermost front contact and armature ofrelay 16, inner, back contact and armature of relay 18, lower, frontcontact and armature of ringing relay 28 and thence over the lower sideof a portion of the cord circuit, and the lOW- or right hand winding ofthe repeating coil, to grounded battery. This tone is repeated to thecalling subscribers line until the subscriber replaces his receiver onits switchhook at which time the answering supervisory relay 8 isreleased to give the disconnect signal. This signal is given by thelighting of the lamp 9 from grounded batarmature and front lilo therelease of the sleeve relay 11, all of the relays of the cord circuitincluding relay 16 and ringing relay 28 are restored to normal. It Willbe noted that the circuit of the ringing relay 28 while being used tocontrol the transmission of the busyback signal, is completed at thelowermost armature and back contact of the flash recall relay 29 so thatif the calling subscriber elects to initiate another call he may signalthe operator as in the case of an ordinary recall by moving hisswitchbook up and down to effect the operation of the flash recall 29which in turn disconnects the busy tone.

It will be understood that the present disclosure is merely typical ofone form of the present invention and there may be many variations andmodifications thereof within the scope of the claims without departingfrom the inventive idea.

lVh-at I claim is:

1. In a telephone system, a telephone exchange, telephone linesterminating at said exchange, a plurality of cord circuit, at saidexchange, means including one of said cord circuits for interconnectingone of said telephone lines as a calling line and another of saidtelephone lines as a called line, means for characterizing saidtelephone lines as busy or idle, a source of busy tone, and meansincluding a busy back key common to said cord circuits for transmittinga busy tone to a calling telephone line when the called telephone lineis busy.

2. In a telephone system, a telephone switchboard, telephone linesterminating at said switchboard, a plurality of cord circuits at eachswitchboard, any one of which cord circuits may be used forinterconnecting one of said telephone'lines as a calling line andanother of said telephone lines as a called line, means forcharacterizing any telephone line as busy or idle, a source of busytone, and means including a busy back key common to said cord circuitsfor controlling the transmission of a busy tone to said callingtelephone line when said called telephone line is busy.

3. In a telephone system, a telephone exchange, telephone lines, meansincluding a cord circuit for interconnecting said telephone lines, asource of ringing current for signalling said telephone lines, a sourceof busy tone, a ringing relay in such cord circuit for controlling theapplication of said ringing current to a called telephone line, andmeans including said ringing relay for connecting said busy tone to saidcalling telephone line when the called line is busy.

4. In a telephone system, a telephone exchange, a calling telephone lineand a' plurality of called party telephone lines terminating at saidexchange, a plurality of cord circuits any one of which may be used forinterconnecting said calling telephone line and a called telephone line,a plurality of sources of ringing current for selectively signalling anyone of the parties on a called telephone line, a source of busy tone, aringing key'for each source of ringing current common to said cordcircuits, said ringing keys serving to control the selection of theproper source of ringing current to signal a desired party on a calledline, source of busy tone, and a busy back key common to said cordcircuits for controlling the'conneetion of said busy tone to saidcalling telephone line when a called line is busy.

5. In a telephone system, a calling telephone line, a plurality ofcalled telephone lines, a plurality'o'f cord circuits, any one of whichmay be used for interconnecting said calling telephone line and adesired called telephone line, means including a recall relay forsignalling when said calling tele phone line initiates a recall, asource of ringing current, a rin ing relay in each cord circuit forcontrolling the connection of ringing current to a called telephoneline, a source of busy tone, a busy back key, means including saidringing relay for connecting said tone to a calling telephone line, anda circuit for said ringing relay controlled by said flash recall relayand by said busyback key.

6. In a telephone system, a calling telephone line, called telephonelines, a; plurality of card circuits, any one of which may be used forinterconnecting said telephone lines, an operators telephone set,automatic listening means responsive to the extension of a cord circuitto said calling telephone line for connecting said operators telephoneset to said cord circuit, means responsive to the completion of theextension of the call through said cord circuit to the called telephoneline for disconnecting said operators telephone set from said cordcircuit, a source of busy tone, a relay for connecting said source ofbusy tone to a calling line, means including a busy back key and saidautomatic listening means serving to control the operation of saidrelay, and means independent of said automatic listening means formaintaining said relay operated.

7. In a telephone system, telephone lines, a plurality of cor-dcircuits, any one of which may be used for interconnecting saidtelephone lines, an operators telephone set, an automatic listeningrelay operated responsive to theestension of a cord circuit to a callingtelephone line, said automatic listening relay serving to connect saidoperators telephone set to said cord circuit, a source of busy tone, abusy back key and a slow releasing relay controlled thereby common tosaid cord circuits, a relay for connecting said source of busy tone tosaid calling line, and means including said automatic listening relayand said slow releasing relay serving to control the operation of saidrelay.

8. In a telephone system, a calling telephone line, a called telephoneline, a plurality of cord circuits any one of which may be used forinterconnecting said telephone lines, an operators telephone set, anautomatic listening relay responsive to the ex tension of a cord circuitto said calling telephone line for connecting said operators telephoneset to said cord circuit, a source of busy tone, a busy tone relay forconnecting said source of busy tone to a calling line, a. busy back keyand a slow releasing relay controlled thereby common to said cordcircuits, and a circuit for said busy tone relay controlled at frontcontacts of said automatic listening relay and said slow releasingrelay.

9. In a telephone system, telephone lines, a plurality of cord circuits,any one of which may be used for interconnecting a calling telephoneline and any one of the other telephone lines, means including a recallrelay for signalling when said calling telephone line initiates arecall, an operators telephone set, an automatic listening relayresponsive to the extension of a cord circuit to a tele phone line forconnecting said operators telephone set to said cord circuit, a sourceofbusy tone, a busy back key and a slow releasing relay controlledthereby common to said cord circuits, a relay for connecting said sourceof busy tone to said calling line, and an operating circuit for saidrelay controlled at contacts of said previously men tioned relays.

10. In a telephone system, a calling telephone line, a plurality ofcalled telephone lines, a plurality of cord circuits, any one of whichmay be used for interconnecting said calling telephone line and any oneof,

said called telephone lines, means including a recall relay forsignalling when said calling telephone line initiates a recall, an operators telephone set, an automatic listening relay responsive to theextension of a cord circuit to a telephone line for connecting saidoperators telephone set to said cord circuit, a source of busy tone, abusy back key and a slow releasing relay controlled thereby common tosaid cord circuits a relay for connecting said source of busy tone tosaid calling line, an operating circuit for said relay controlled atcontacts of said previous ly mentioned relays, and a locking circuit forsaid busy tone relay independent of said slow releasing relay and saidautomatic listening relay.

In Witness whereof, I hereunto subscribe my name this 2nd day of May A.D. 1930. WILLIAM J. VINCENT.

DISCLAIMER 1,821,193.-Wtlltam J. Vincent, Rochester, N. Y.

dated September 1, 1931. Disclaimer filed October 5, 1932, RochesterTelephone Corporation.

Herebv enters this disclaimer to so much of claims 1 and 2 wherein theterm telephone lines is not limited to subscribers or substationtelephone lines.

[Ofiicial Gazette November 1, 1932.]

TELEPHONE SYSTEM. Patent by the assignee,

